A filter-tipped cigarette comprises a tobacco portion having an outer end and an inner end; and a filter butt-connected to the inner end of the tobacco portion and connected to the tobacco portion by a sleeve wound about the filter and partly about the tobacco portion. The outer end of the tobacco portion is free (i.e. the tobacco is left exposed), constitutes the tip of the filter-tipped cigarette, and is used by the user to light the filter-tipped cigarette.
A good-quality filter-tipped cigarette must be filled firmly, i.e. contain a sufficient amount of tobacco, at the tip. Conversely, a filter-tipped cigarette with an ‘empty’ tip, i.e. containing no tobacco, is considered poor quality. By the end of the manufacturing process, almost all filter-tipped cigarettes have perfectly filled tips, but the mechanical stress they are subjected to during subsequent transfer and packing may result in tobacco fallout from the tips. So, after forming and before wrapping each group of filter-tipped cigarettes, the tips are quality controlled optically, and the group is rejected if even only one of the filter-tipped cigarettes in it has a poorly filled tip (in other words, since a standard group of filter-tipped cigarettes comprises twenty cigarettes, nineteen good cigarettes must be sacrificed to remove one flawed one).
On filter-tipped cigarette manufacturing systems, poorly filled tips are responsible for the rejection of large numbers of cigarettes, which means substantial economic losses for which a valid solution has not yet been devised.
Patent Application GB2284339 describes a filter-tipped cigarette in which the tobacco portion is divided into two axially separable parts, but in which the tip (where the tobacco is exposed) has no protection whatsoever.
Patent Application GB810759 describes a cigarette with no filter and comprising two paper hoods covering the two opposite ends of the tobacco portion, and both of which are removable axially to smoke the cigarette. Applying the paper hoods, however, involves a particularly complex folding operation, which cannot be performed correctly at high speed. In other words, on a modern cigarette manufacturing machine (capable of producing up to 20,000 cigarettes a minute), the folding operation would result in a reduction in speed that would be unacceptable.